The ultimate goals of this project are to determine how arterial stiffness properties influence myocardial structure and function and contribute to cardiovascular morbidity and mortality. A. To determine whether ultrasonic indices of carotid arterial structure are major determinants of arterial stiffness properties, we measured thickness and diameter of the common carotid artery (CCA) from B-mode ultrasonography and the augmentation index (AGI), derived from applanation tonometry of the CCA, in 84 healthy normotensive BLSA volunteers aged 27-95 years. Although systolic blood pressure (r=0.31), CCA thickness (r=0.58), CCA systolic diameter (r=0.30), and AGI/height (r=0.43) all correlated directly with age, AGI/height did not correlate with either ultrasonic measurement. In addition, AGI/height was unrelated to four elasticity indices derived from CCA ultrasound, distensibility coefficient, cross-sectional compliance, pressure-strain ela ic modulus, and young's modulus. B To determine whether growth hormone or sex steroid supplementation ameliorates arterial stiffness properties in older adults with deficiencies of these substances, we are measuring pulse wave velocity and AGI in men and women aged 65 years and older, before and after hormonal replacement. C. We are testing the hypothesis that 1-2 years of home-based aerobic exercise training can reduce arterial stiffness in the muylticenter NIH-sponsored Activities Counseling Trial of 810 subjects 35-75 years old. D. We have examined the contribution of arterial stiffness to left ventricular (LV) mass in 695 men and 616 women from Taiwan (Contract #N01-AG-02-2118). In both sexes, the major predictors of LV mass were systolic blood pressure, body surface area and age; AGI contributed minimally (r2less than or equal to 0.006) to LV mass in either sex. E. A multicenter study to determine whether arterial stiffness is an independent risk factor for cardiovascular events in elderly free-living persons has been developed by the Epidemiology Demography Biometry Program of the intramural NIA. F. A method for calculation of charteristic impedance of the arterial tree from non-invasiv measurements of central arterial pressure and flow has recently been developed. G. We are performing follow-up measurements of arterial stiffness on endurance trained older men and their sedentary age peers, initially studied in 1989-1991 to determine whether chronic endurance training attenuates the normal age-associated increase in arterial stiffness. H. To determine whether aerobic exercise training can reduce the elevated arterial stiffness of older heart failure patients and whether such changes in arterial stiffness are related to training-induced improvement of aerobic performance, we will measure arterial stiffness and peak VO2 before and after a 3 month program of aerobic training.